He hasn't been on this thread for a pretty long time! He engineered it specifically for 2 LED's. You might check out another 'ible:https://www.instructables.com/id/Super-Efficient-J...Granted the more LED's you put in this circuit, the shorter the battery life. This circuit boosts the voltage to use a battery longer, but of course doesn't prolong actual amp-hours available from the battery. 1 battery can power 1 LED for weeks, but 12 LED's would be way less time. :)